This grant application is in response to PAR-03-078 "From Intervention Development to Services: Exploratory Research Grants (R34)." The proposed study will conduct a preliminary evaluation of a school based treatment program for middle school youth with ADHD (Challenging Horizons Program: CHP). In addition, investigators will complete the development of fidelity assessment procedures and other steps necessary according to current treatment development guidelines for the subsequent submission of a application for a full clinical trial. The CHP was initially developed in 1999 as a result of 1) the dearth of research on psychosocial treatments for ADHD in adolescents, 2) promising results in a few psychosocial treatment studies suggesting improvements in multiple domains of functioning in adolescents with ADHD, and 3) limitations associated with reliance on psychoactive medications as the only method of treatment for adolescents with ADHD. During the past five years a treatment manual and training procedures have been developed and preliminary studies have produced encouraging results. The program has been piloted at two additional sites (USC - Smith; WPIC - Molina) and their teams have contributed to the continued development and pilot testing of the procedures (see preliminary studies). Based on this work, we propose this study to complete the initial stages of the treatment development process. In addition to completing the development of fidelity assessment procedures and making final revisions to the training and treatment manuals, we will conduct a small randomized clinical trial of the CHP. A total of 44 adolescents diagnosed with ADHD will be recruited, with nearly two thirds (28) randomized to the after school program and the remaining participants (16) randomized to a community care condition. At each school two cohorts of 11 adolescents (7 treatment and 4 controls) will be treated for five months and followed for six months post treatment. Treatment will consist of academic, social, and organizational skills training, teacher consultation, family therapy, and therapeutic recreation. Primary outcome measures, including academic performance and behavior rating scales, will be collected monthly during treatment and at a 6 month follow-up point. Multilevel modeling will be used to assess group effects and treatment by medication interactions (randomization will be stratified by medication status at baseline). Furthermore, the analysis will examine rates of clinically significant change. The results of this study will provide effect size data needed to project sample size for our clinical trial as well as generate hypotheses regarding treatment moderators and mediators.